sistersinhim is absolutely correct. It's easy (even if you're a trained physical therapist) to minimize recovery from a problem knee. It takes longer than a primary surgery that is very straightforward with no problems at all. Unfortunately, your current therapist doesn't understand this. If you want to stay with her, I'm afraid you'll just have to overlook this lack of understanding.
I'm proud of you for recognizing in your gut that the therapist's comments were out of line and incorrect. Since you don't have that much longer before you see your surgeon again, I suggest you continue with the therapist if you feel you are benefiting from it. Then when you see your surgeon, talk to him about it and see what he recommends for additional therapy. Whether you do or do not need mental counseling, it was totally unprofessional for a therapist to say something like that to a patient. If she felt you needed this type of help, she should have made a report back to the surgeon documenting why she felt that way.
You have some options if you want to continue to see this therapist. At your next appointment, you can bring it up, remind her that she is not trained in mental health diagnosis, tell her you were offended and ask that she stick to physical therapy issues from now on. Or....if you are not comfortable bringing this up to her, you could wait and have this conversation if she ever mentions it again. It also wouldn't hurt to talk to her supervisor about it as well.
This is one of those cases where you are entitled to stand up for yourself and the way you are treated by those on your medical team. If you provide this feedback to the therapist, her supervisor, and your surgeon, it signals that you recognize she was out of line and you are concerned this might happen to others who may be more vulnerable than you are.
Try not to worry about your knee. You're still in the very early stages of your recovery. Use your walking aids as long as you need them. There is no hurry. You want to keep working WITH your knee as it heals, not fight against what it needs. Keep reminding yourself that your knee is in control and it will heal.